A vane type oscillating actuator, for example, as disclosed in Patent Document 1 is commonly known as the above type of oscillating actuator. In this vane type oscillating actuator, a vane mounted on a shaft and a fixed wall which defines an oscillation angle of the vane are disposed inside a body which is formed in a cylindrical shape. The vane is oscillated by alternatively supplying and exhausting a compressed air to and from pressure chambers located on each side of the vane through ports, and an oscillation motion of the vane is output via the shaft so that the shaft oscillates a load such as a robot hand, a transportation table or the like by a predetermined angle.
The oscillating actuator is connected to a device having the load (load device) in a certain orientation by using screws or the like and is used in a state that the shaft is connected to the load. In some cases, however, the oscillation start position of the shaft when the oscillating actuator is connected to the load device may not match the oscillation start position of the load depending on the load device, or the oscillation start position of the load may need to be changed when performing a different operation process. In such cases, it is preferable that the oscillation start position of the shaft of the oscillating actuator can be adjusted for the oscillation start position of the load.
This can be achieved, for example, by changing the mounting orientation of the oscillating actuator to the load device in the rotation direction of the shaft. However, a technique to easily achieve the changing has not been proposed. Moreover, it is not preferable that the load device itself is provided with a configuration which allows the mounting orientation of the oscillating actuator to be changed, since it leads to a complicated structure or increased cost. Accordingly, there is a need for an oscillating actuator which is capable of changing the oscillation start position of the shaft.